1. Field of the Invention
The invention relates to an image-pickup apparatus, method and computer readable recording medium.
2. Discussion of the Related Art
Electric digital camera technology has recently become increasingly popular. In this form of technology, an image is normally imaged by a CCD array. Subsequently, the images are stored on the camera in storage media such as a semiconductor memory array. At a later stage, the images are downloaded from the CCD device to a computer or other similar device, in which they are subjected to subsequent manipulation and printing in the course of requirements.
In a digital camera the preparation for photographing images (or capturing images) has previously been initiated from the time of inputting a release signal as an instruction signal for the photographing.
There included during preparatory process are several steps such as setting a bias voltage applied to a CCD device and preparing for outputting a voice output, some of which take a relatively long time before suitably stabilized as to become fully operative. This may result in a prolonged release time lag in proportion to the time length of the preparatory waiting period.
Such a difficulty can be obviated for example by applying a bias voltage applied to CCD substrate prior to photographing so that the time lag is eliminated.
This method, however, may result in a drawback of degrading image qualities from the so-called “blooming effect” which is caused by electric charges spilled out to surrounding pixels in CCD device when a high-luminance object is present in the field of view to be photographed.
In another case when voice output means is put always on, the time lag can also be reduced. This may cause, however, a further drawback of the increase in power consumption caused by continuous turning on of the circuit, which also affects battery life.
In regard to the application of voltage to a CCD device, a circuit has previously disclosed in Japanese Laid-Open Patent Application No. 2001-177774 for changing promptly the bias voltage applied to the CCD device. Even by the method described in that application, however, the change of bias voltage generally takes a relatively long time.
Therefore, when the steps of changing the bias voltage are implemented following the photographing, the release time lag is prolonged in proportion to the time corresponding to the waiting period needed for stabilizing the bias circuit voltage.
In contrast to the '774 application, the present invention discloses a method of reducing the release time lag by initiating bias voltage setting steps under predetermined conditions prior to the photographing, which will be descried below.
In addition, although another circuit has been disclosed in Japanese Laid-Open Patent Application No. 05-103273 for promptly changing CCD bias voltages, the method in accordance with the present invention is also different from this application '273.
It is therefore desirable to provide methods of obviating previous difficulties noted earlier.
Difficulties have persisted such as unduly prolonged release time lag in proportion to time required for the setting of CCD bias voltage or for preparing suitable voice output process, the degradation of image qualities, which is caused by the above-mentioned blooming effect when a high-luminance object is present in the field of view to be photographed, and the increase in power consumption during preparatory steps of voice output.